Continuing fascination of exploration in natural substances from microorganisms†

Takahashi, Yōko

doi:10.1080/09168451.2016.1248368

Cited by 6 publications

(2 citation statements)

References 20 publications

(14 reference statements)

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“…Currently, some 642 strains of actinomycetes have been isolated from 16 plant root locations, about 80% of which are rare. Two new genera ( Phytohabitans sufuscus and Rhizocola hellebori ) plus seven new species have, so far, been proposed through taxonomic study of these strains [ 19 , 20 , 21 ].…”

Section: Historical Discovery Of Novel Compounds From Actinomycetementioning

confidence: 99%

Actinomycetes, an Inexhaustible Source of Naturally Occurring Antibiotics

2018

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Global public health faces a desperate situation, due to the lack of effective antibiotics. Coordinated steps need to be taken, worldwide, to rectify this situation and protect the advances in modern medicine made over the last 100 years. Work at Japan’s Kitasato Institute has been in the vanguard of many such advances, and work is being proactively tailored to promote the discovery of urgently needed antimicrobials. Efforts are being concentrated on actinomycetes, the proven source of most modern antibiotics. We devised a novel physicochemical screening mechanism, whereby simple physico-chemical properties, in conjunction with related detection methods, such as LC/MS, LC/UV, and polarity, could be used to identify or predict new compounds in a culture broth, simply by comparing results with existing databases. New compounds are isolated, purified, and their structure determined before being tested for any bioactivity. We used lyophilized actinomycete strains from the Kitasato Microbial Library, most more than 35 years old, and found 330 strains were producers of useful bioactive substances. We also tested organisms found in fresh samples collected in the complex environments from around plant roots, as well as from sediments of mangrove forests and oceans, resulting in the discovery of 36 novel compounds from 11 actinomycete strains. A compound, designated iminimycin, containing an iminium ion in the structure was discovered from the culture broth of Streptomyces griseus OS-3601, which had been stored for a long time as a streptomycin-producing strain. This represented the first iminium ion discovery in actinomycetes. Compounds with a cyclopentadecane skeleton containing 5,6-dihydro-4-hydroxyl-2-pyrone ring and tetrahydrofuran ring, designated mangromicins, were isolated from the culture broth of Lechevalieria aerocolonigenes K10-0216 obtained from sediment in a mangrove forest. These structures are extremely unique among natural compounds. From the same culture broth, new steroid compounds, named K10-0216 KA and KB, and other new compounds having a thiazole and a pyridine ring, named pyrizomicin A and B, were discovered. New substances can be found from actinomycetes that have been exhaustively studied. Novel compounds with different skeletons can be found from a single broth of one strain. The sought after new antibiotics will arise from continued exploitation of the actinomycetes, especially rare actinomycetes. Work on new organisms and samples should be augmented by re-examination of known actinomycetes already in storage. New research should also be carried out on the manipulation of culture media, thereby stimulating actinomycete strains to produce novel chemicals. The establishment of wide-ranging international research collaborations will facilitate and expedite the efficient and timely discovery and provision of bioactive compounds to help maintain and promote advances in global public health.

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Section: Historical Discovery Of Novel Compounds From Actinomycetementioning

confidence: 99%

Actinomycetes, an Inexhaustible Source of Naturally Occurring Antibiotics

2018

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“…(Kautsar et al, 2020) This knowledge associated with the use of technologies such as recombinant DNA and Genome shuffling may point to the future of exploratory engineering in microbes with biosynthetic potential, being known as the bacteria of the genus Streptomyces, or new microorganisms from different natural sources (Fig. 2) [32][33][34].…”

Section: Developmentmentioning

confidence: 99%

Frontiers in the search for new antimicrobials: new perspectives

Silva¹,

Martins²,

Evangelho³

et al. 2023

Braz. J. Develop.

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Infections caused by bacteria and fungi resistant to antimicrobials are one of the main public health problems in the world. These microorganisms are associated with high rates of morbidity and mortality and also with high hospital costs. Their emergence and spread are closely related to the excessive and inappropriate use of antimicrobials in medical and veterinary practices and in animal production. For the treatment of Candida spp. there are few classes of antifungals available for treatment, the classes being: azole derivatives, polyenes and echinocandins. The class of azoles includes imidazole derivatives (ketoconazole, miconazole, clotrimazole), triazole derivatives (fluconazole, itraconazole and voriconazole) and posaconazole. These drugs can be used for topical us as well as in the treatment and prophylaxis of invasive infections. The wide use of these drugs has led to a strong selection of strains resistant to them, which is increasingly growing. The need to produce new antimicrobial drugs requires different strategies, among which we highlight the importance of bioprospecting for secondary metabolites of environmental bacteria and fungi with potential antimicrobial activity.

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